Draw-in type flush latch



July 12, 1955 w. R. ANDREWS 2,712,955

DRAW-IN TYPE FLUSH LATCH Filed Sept. l5, 1952 2 Sheets-Sheet l INI/EN TOR. Wam/v P. Awa/@m5 BY an@ July 12, 1955 w. R. ANDREWS' DRAW-IN TYPE FLUSH LATCH 2 Sheets-Sheet 2 FiledY Sept. l5, 1952 INVENTOR. WELDO/v A/VQEz-'Ws O'I/ 84X /qTTEh/EYS United States Patent DRAW-IN TYPE FLUSH LATCH Weldon R. Andrews, Seattle, Wash., assignor to Clark Hartwell and Eleanor M. Hartwell, copartners doing business as Hartwell Aviation Supply Company, Los Angeles, Calif.

Application September 15, 1952, Serial No. 309,710

9 Claims. (Cl. 292-113) My invention relates to draw-in type flush latches, and included in the objects of my invention are:

First, to provide a latch which is particularly designed for use under circumstances wherein a latch hook or arm can be initially extended to engage its keeper and can then be retracted to draw the latch and keeper carrying structures together, and wherein the latch, when closed, will lie flush with the surface of such structures. For example, the latch is particularly suitable for securing removable panels or hinged panels or doors employed in aircraft.

Second, to provide a latch of this type which is inherently constructed so that pressure differences between the interior and exterior of the structure secured by the latch produces no appreciably unbalanced force which would cause the latch to snap open.

Third, to provide a latch of this type wherein the latch hook may have a substantial reach so as to engage its keeper from a distance to draw the mating structures together.

Fourth, to provide a latch of this type wherein the lush fitting portions may be variously shaped to conform to any curvature of the surfaces of the mating structures without altering the operation of the latch, that is, the ush fitting portions may be dat, convex or concave in contour.

Fifth, to provide a latch of this type which is so arranged that, when open, the normally ush fitting portions form a substantial and readily grasped handle.

With the above and other objects in view as may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figure l is a plan view of one form of my latch with portions broken away and in section and showing the latch set in a panel structure, the surrounding structure being shown fragmentarily.

Figure 2 is a longitudinal sectional View through 2 2 of Figure l showing the latch in its closed position.

Figure 3 is a transverse sectional view through 3 3 of Figure 2..

Figure 4 is a transverse sectional view through 4-4 of Figure 2.

Figure 5 is a longitudinal sectional view similar to Figure 1 but showing the latch in its open position.

Figure 6 is a side view of 'a modified latch designed to conform to convex surfaces.

Figure 7 is a side View of my latch Vmodified to favor concave surfaces.

Figure 8 is a 'reduced plan view of another modiled form of my latch.

Figure 9 is a longitudinal sectional view thereof, taken through 9--9 of Figure 8.

Figure l0 is a bottom view thereof.

Figure ll is a transverse sectional view thereof.

My draw-in type latch is intended primarily for use in aircraft although it may be employed wherever a drawin type flush latch is desired. For purposes of illustration, my latch is shown asset Y ture.

2,7i2,955 Patented July 12, 1955 ICC in a door or panel structure 1 having a marginal ange 2 of channel-shaped cross section and adapted to tit within a mating frame 3 of a surrounding body structure 4. The body structure or its frame is provided with one or more keeper mountings 5 which are preferably adjustable and which carry at their extremities a transverse keeper bar 6. The door or panel structure is provided with an accommodation slot 7 disposed in registry with each keeper bar.

At the inner side of the door or panel structure, adjacent the end of the accommodation slot 7, remote from the margin of the panel structure, is a pair of brackets 11. A handle 12 is adapted to fit within the accommodation slot 7; the handle 12 may be formed of sheet material and is channel-shaped in cross section so that the web I so as to curve downwardly and clear the journal pin 14.

The hook members are joined together by spacers 17, and extended ends form hook portions 18 which straddle the keeper mounting 5 and engage the keeper bar 6. A spring 19 is coiled about the tubular journal 15, one end bears against the handle 12 and the other end of the spring bears against one of the spacers 17 so as to urge the hook members or latching arms downwardly away from handle 12, or if the latching arms are restrained, to pivot the handle outwardly to the position shown in Figure 5.

The handle 12 is provided with a slot 29 which receives a trigger member 21. The trigger member is T-shaped in side aspect and is formed of sheet metal and folded so as to be U-shaped or channel-shaped in cross section. The web of the channel thus formed completely lls the slot 20. A cross pin 22 extends through the flanges of the handle 12 and trigger member 21 so that the web or trigger member may be pivoted between a iiush portion in the handle 12 and in an angular position. A spring 23 is coiled about the pin 22 and bears against the trigger member and handle in such a'manner as to urge the trigger member towards its hush position shown in Figure 2. It should be noted in Figure 5 that the trigger member is shown in an angular position in opposition to the action af the spring 23. The legs of the trigger member terminate in hooked ends 24 which are adapted to straddle the hooked portions 19 of the hook members or latching arms 16 and engage the keeper bar 6.

Operation of the latch is as follows:

Assuming the latch to be in the position, shown in Figure 2, the latch is released by pressing in the direction marked A on the end of the trigger member adjacent the margin of the panel structure. This pivots the hook ends 24 clear of the keeper bar 6. The spring 19 urges the handle 12 in a clockwise direction as viewed in Figures 2 and 5, causing the hook portions 1S of the hook member to clear the keeper bar. The outwardly extending end of the handle 12 may then function as a handle to remove or open the panel struc- To close the latch, the handle 12 is rotated counterclockwise against the action of the spring 19, causing the hook member to engage and draw on the keeper bar. The trigger member automatically snaps into place as the handle 12 is forced flush with the panel structure.

In the structure shown in Figures l through 5, the web portions of the handle 12 and trigger member 21 Vthe' hook member.

of channel-shaped cross section is provided. This han-V dle may be essentially the samey as the handle i2 and The structure here Vshown is, in more respects, similar to the iirst described structure except that the trigger member does not engage the same keeper bar as ln this construction, a handle 3i itV is arranged to be dat, concaveV or convex. The vflanges of the handle 3i are connected near one end of the handle by a bushing 32, corresponding to the bushing 13. A journal 33, similar to the tubular journal 15, pivotally supports a hookV member or latching arm 34. The hook member* may be formed of two similar members, preferably riveted together, except for its pivoted end which is arranged to forma yoke 35. A spring 36, corresponding to the spring 19, is coiled about the journal 33 and is arranged to bear against g the handle 31 and a cross pin 37, provided in the yoke ends of the hook member. The extended end of the hook member or latching arm is provided with a hook portion 38, corresponding to the hook portion 18 of the rst described structure. The handle 31 is provided with a slot 39 which receives a trigger member 46 of channel-shaped cross section and is arranged that its web lls the slot 39.

As in the first described structure, the triggermember journals on a cross pin 41, extending between the ilanges of the handle 31. The flanges of the trigger member terminate in hooks 42, adapted to straddle the hook member 34 and engage the protruding ends of an anchor pin 43, extending transversely through the hook member or latching arm 34. A spring 44 ,h

is wrapped on the cross pin 41 and its extremities are arranged to bear against the handle 31 and, trigger member 40 in the direction to urge the hooks 42'into engagement with the anchor pin 43. It will be noted that the trigger member 40 is arranged to pivot in the opposite direction Vfrom the trigger member 21. However, the direction in which either of these members may pivot is a matterof choice, depending on which side it is desired to engage the keeper. In order that either of the trigger members 21 or 40 may move into ush position to be restrained from further movement, the respective webs of the trigger members may form stops 45 and V46, respectively, which engage under the web of the corresponding handle.

Operation of the structure, shown in Figures 8-171, inclusive, is essentially the same as the first described structure, except that the trigger member 40 engages the anchor pin 43 carried by the hook member rather than the keeperl bar 6. v

lt will be observed that the'trigger member may be centered relative Vto its Ypivoted axis so that pressure 1' dierentials between the inside and outside of theV structure in which the latch is mounted need have little or no effect to cause the latch to release.

Having fully described my invention, it is to be Y understood that I do not wish to be limited to the details herein set forth, but my invention is of the full Y Y end of said'handle member, said latching member having. means at itsY extremity for engaging a keeper; and

. 4` a trigger member pivotally mounted in said handle member and cooperating with said latching member to secure said latching member in its keeper engaging position.

2. A latch structure, comprising: a pivotable handle member having a fulcrum axis near one end, said handle member being channel-shaped in cross section, the web thereof being shaped to conform to the'surface of a structure in which said handle member is adapted to beV mounted, said' web having a slot therein; a trigger member pivotally supportedby said handle member, said trigger member being of channelshaped cross section and the web thereof adapted to Y occupy a position ush with the web of said handle member; a latching member pivotally connected to said handle member immediately beyond the fulcrum axis of said handle and extending around and past said fulcrum axis for movement of its pivoted enclin an are about the fulcrum axis of said handle and having latching means at its extremity adapted for engagement with a keeper; said trigger member adapted to cooperate with said latching member to secure said latching member against pivotal movement Vrelative to said handle and maintain said latching member in engagement with said keeper.

3. A latch structure, comprising: a pivotable handle member of channel-shaped cross section forming a web contoured to be disposed flush with a surrounding structure in which the latch is intended to be mounted,

the web of said handle member having an aperture; aV

trigger member pivotably mounted in said handle member and having a portion adapted to ll said aperture and be disposed flush with the web of said handlev channel-shaped cross section forming a web contoured to Y be disposed flush with a surrounding structure in whichV the latch structure is intended to be mounted, said handle member having a fulcrum Vaxis near one end; a latchingA arm pivotally attached to said handle member at saidv one end immediately beyond said fulcrum axis and extending around and past said fulcrum axis toward the other end of said handle member, said latching armY having vmeans at its extremity for engagement with aV keeper, the pivoted end of said latching arm movable in an arc about the fulcrum axis of said handle member, said latching arm also movable between a latching position in approximate parallelism With said handle andv an'angular releasing position; and a trigger member pivotally mounted in said handle member and having a manually engageable portion pivotable between a flush position in the web of the handle member and an angular position, and a latching portion adapted to traverse said latching arm and cooperating with said latching arm-to restrain said latching arm in its latching position when said manually engageable portion is in its flush position. j

5. A latch structure as set forth `in claim 4,'wherein: the latching portion of said trigger member is adapted for engagement with the keeper engageable by said latching arm. Y

6. A latch structure as set forth in claim 4, wherein: the latching arm carries a second keeper and the latching portion of said trigger member engages said second keeper.

7. A latch structure, comprising: a handle member of channel-shaped cross section forming a web contoured to be disposed flush with a surrounding structure inwhich the latch structure is intendedto be mounted, said handleY member'having a-fulcrum axis near one encina latching arm pivotally attached to said handle member at said one end immediately beyond said fulcrum axis and extending around and past said fulcrum axis toward the other end of said handle member, said latching arm having means at its extremity for engagement with a keeper, the pivoted end of said latching arm movable in an arc about the fulcrum axis of said handle member, said latching arm also movable between a latching position in approximate parallelism with said handle and an angular releasing position; a trigger member pivotally mounted in said handle member and having a manually engageable portion pivotable between a ush position in the web of the handle member and an angular position, and a latching portion traversing said latching arm and cooperating with said latching arm to restrain said latching arm in its latching position; a rst spring disposed so as to urge said latching arm toward its angular position; and a second spring disposed so as to urge said trigger member toward its ush position and said latching portion toward its latching arm restraining position` 8. A latch structure as set forth in claim 7, wherein: the latching portion of said trigger member is adapted for engagement with the keeper engageable by said latching afm.

9. A latch structure as set forth in claim 7, wherein: the latching arm carries a second keeper and the latching portion of said trigger member engages said second keeper.

References Cited in the file of this patent UNETED STATES PATENTS 2,424,962 Best Aug. 5, 1947 2,477,472 Wright July 26, 1949 FOREIGN PATENTS 981,093 France Jan. 10, 1951 

